Allow me to get out some luddite hate first:

-there's already an app for getting feedback if you don't understand... it's called RAISING YOUR HAND!!!!!11!

-are you going to add a "distractometer" to log how many times people are distracted by using and checking the app?

Ok, now that that's done. I would actually lose the "o-meter" phrasing and have the app simply say "Confused" and "Understand". In fact, you could even lose the "understand" interaction. I doubt people will be hitting a button all the time every time they "understand" something during a lecture. Just have one button for confusion.

Is there a way to post feedback (anonymously) at the end of a lecture?

Radical piviot: you know what this model of instant feedback would be good for? Occupy Wall Street and general assemblies.

Raising your hand only tells the professor that you, an individual, are confused. Interruptions by a single student that doesn't understand the material, when the rest of the class does, might actually cause the professor to focus too much attention on a subject that doesn't need it.

This is far better. There will always be a couple people that are not following. If the professor is getting 90% "I understood" responses, he can simply mention that anyone with questions on that topic is free to meet them after class, while the rest of the time can be spent on topics where there is a lower rate of understanding.

Thanks for the feedback! In large classes students tend to be reluctant to raise their hands (especially in classes with 200+ students). ESL students are also unlikely to raise their hand and say they don't get it. I actually tested the app in 3 first year classes and it didn't seem to be distracting.

I'm hoping to add a feature for leaving feedback at the end of a lecture, great idea!

Also great idea on the Occupy Wall Street idea!

I go to a small college where average class size is around 20 students. People hardly ever raise their hand.

Overwhelming majority of students are deathly afraid of looking like an idiot by raising their hand. It happens everywhere, not just large classrooms.

I think this is a great idea.

I went to a small college too... In a class of 10-20, it was pretty easy for the professors to know when we were confused since she was looking at each of us.

Exactly right. I teach at a uni in South Korea. Students who never lived/traveled outside the country will never, ever raise their hands if they don't understand. Not only that, but if you ask them outright, they will nod and say clearly, "yes, I understand", and then turn to their best friends and say in Korean, "I actually don't understand any of it".

This app would be a tremendous help not just to my classes (I've been here a long while, and know how to read the signs of confusion & check understanding), but also to the classes of newbies in Korea.

New teachers here sometimes go for months naively asking students "do you understand this stuff" and believing it to be true.

If Koreans could vote on this anonymously, I think they would actually do that at every opportunity.

I like cutting the input down to only "confused". You can just assume the remaining people logged into that "room" are not confused - either they understand it or are comfortably making sense of it.

Wish I had that for my calc lectures...

This can also be a problem in my opinion. Imagine you are only able to enter "confused". Then as soon you are using this app in a class room everyone who sees that you are using the app knows that you will enter "confused". This is a problem for many people I guess. You don't wanna lose your face sometimes. Hm - one solution to this could be to make the UI of the app absolutely generic or exchangeable. I would also build in a random delay between the "tap" on the button and the actual transmission of the data to the "lecturer". The delay can be minimal but this makes it hard to track it back to the source.

Just some random thoughts:

I think it would be awesome if you can generalize the idea for online lectures also (coursera, khan academy, udacity, etc). Since videos are not real time, letting students hit "confused" for certain segment of an online video will let the developers splice in a better explanation for bad parts of a video or even let them a/b test two different versions of a segment of the same video.

And also, instead of a confused button, maybe allow them to optionally elaborate on the source of their confusion? A potential solution for online videos is via timed comments (similar to how soundcloud does it, except maybe with interval of confusions instead http://37signals.com/svn/posts/1143-soundcloud-expands-the-a...)

I can definitely see the appeal of this - like you mentioned in your blog post, there's always worry that others will think you're stupid or something for not understanding something.

That having been said, I had a few questions/concerns:

- How would it work when there were specific gaps? It might be helpful if comments could be included to the instructor when the rating is provided. That would allow the teacher to reinforce those particular topics.

- How would you guarantee participation? If, for example, only people that don't understand the topic speak up, wouldn't that skew the data presented to the teacher?

Great points. I'm definitely interested in allowing students to provide more in-depth feedback.

Participation is a much trickier issue. In the classes that I tested in about 40 - 60% of the students actually used it. I was thinking of weighting the confusion 'votes' based on 'active' users.

I'm hoping that through feedback form professors I'll be able to add features that make it more worth while for students.

That's a lot more participation than I would have guessed, that's pretty awesome! Thanks for the info, and I look forward to seeing this getting more widespread use :)

I like the idea of the app. Your website looks horrific on ie. I know, no one uses ie any more, but I am forced to use it at work and there are probably several million other people in the same boat. You should fix it if possible.

Yikes, fixing how it looks in ie9+ will be added to my todo list.

I like it. I think you've got one too many lines, though: you don't need both a confuse-o-meter and an understand-o-meter - they're reporting the same metric. I'd consider averaging them into one line for overall sentiment.